Refining of glyceride oils



March 20, 1956 H, M, WEBER REFINING OF GLYCERIDE OILS Filed May 28, 1952 m93 html E@ Sherwin-Williams Company, Cleveland, (Ehio, a corporation of Ohio Application May 2s, 1952, serial No. 290,387 claims. (ci. 26o- 424) present invention relates to an improved method of refining `glyceride oils such as vegetable and animal oils more particularly to a continuous method of refining .Such oils while dissolved in a solvent therefor. As used herein, the term `oil will be used lto denote vegetable oils and animal oils such as linseed, cottonseed, castor, soy, peanut, hempseed, sunflower seed, Voiticica, tung, coconut, corn, menhaden, sardine, whale, beef tallow, inutton fallow, and the like.

Crude glyceride oils containv many impurities which must be removed therefrom in order to produce a commercially acceptable product. These impurities include ffoots, break, color bodies, phosphatides, lipids, free `fatty acids, gums and other materials which are undesirable. Fonts are materials which tendre settle out of the oil onstnding VVand may be vremoved from the oil by a edious'ltra'tion operation or by'treatment'with water or other refining agent. Break includes. those materials vhieh are soluble in the crude oil but which become 'in'- soluble Vand settle out when the oil is heated and these maybe removed without heating by treatment of the 'oil With various refining agents. As is Well known, the 'use of `sodi-um hydroxide as a refining agent will form soaps 1with the free fatty acids present, Awhich soaps 'are subsequently removed from the oil together with foot`s`'a`nd Votherimpurities.

Ih 'the past, crude oil has usually been treated'with relatively concentrated aqueous solutions of the refining agents. -Such methods have involved many disadvantages schas uneconomieal oil'losses, formation, of :emulsions `which seriously impede separation of the refined oil from the impurities and an incomplete removal of the im'- puritles. 4\cccai'di`ng to the present invention, the various operational l-difiioulties are avoided, but of greater importance is "the l-in'c'sieased oil recovery and increasedrerrioval fof impurities. By the'present method, losses of glycerideoils encountered `inec`:o1`1 vention"al refining methods 'are 'reduced to "a niinimum. v'ilVhe'reas losses of glyceride y`o'i1"s us"ed to nin about v3% for more of the *oil being'rened, these losses can now be cutto 2% vor'eve'n less. The recovery wof'this Aadditional oil, particularly von va commercial badis, results in greateconomic advantages. Bypriorart methods removal ofsom'e impurities was a tedious and expensive operation but'by the present invention the removal 'of Such impurities is simpleand economical.

Anotherfeature of the present invention is the use -of very dilute"solutions of the refining agents. In the past concentrated solutions were requiredso as ltoreduce the total Aamount of solution or Vmixtures of refining `agents used and/ or to Vreduce the amount oftinert rsolids which United States Patent' werejequired as filter aids whereby the removal of the precipitated i material from the oil by filtration l-or other means was facilta'ted'andthe formation ofemulsionsw'as avoided. 'The refining solutions -of thepresent invention are? more vdilute than those previously used fand,"as willfbe hereinafter, improved contactvvitlftlieoil isfob- 2,"739,164 Patented AMair. 2Q, A1 956 tained "and sparation of the refined oil from the residues is easily accomplished.

It therefore lan object of the present invention to provide an improved method for refining vegetable and animal glyceride oils. l

Another object is to provide a refining method in which very dilute solutions of the reiining agents are used.

A further object is to provide a method for refining oils by which separation of the refined oil from the reiiviiig 'agent' and impurities is easily accomplished.

Still another object is to provide a refining method by which increased amounts of the impurities are removed from the oil While encountering lower oil losses.

A `still further 'object of the invention is to provide a continuous 'method for refining such oils.

vThe accompanying drawing which forms a part of' this specification is a ow sheet of an example of the process embodying the features of the present invention and will be desoribed in detail hereinafter.

According to the present invention, the oil to ybe reiined `is preferably in the -form of a miscella containing a hydrocarbon solvent for glyceride oils, such as hexane or heptane, or other low boiling aliphatic or aromatic hydrocarbon or chlorinated hydrocarbons such as ethylene dicliloride, and an aqueous solution of a monohydric aliphtic a'lcohol such as ethyl, isopropyl or other low moleeularweight aliphatic alcohol. The proportions of the aqueous alcohol, hexane and oil in thel miscella are 'such that 'the entire miscella is a true'soluticn. The Vamount of aqueous alcoholsatuates the hexane and oil solution so that additional Vquantities of alcohol -will not-'dissolve in 'the miscella. In view of the presence of both alcohol and hydrocarbon solvent the miscella may be said to comprise oil and a single phase dual solvent. Although such a miscella may be obtained directly Vfrom certain oil extraction processes, nevertheless any oil, such as an expressed oil, or other 'type of miscella, such as a simple oilsolvent miscella, can be treated according to the present invention. :An oil-hydrocarbon solvent miscella may be used'diretly in the'present process since it will become Satu'rated'with alcohol during the first refining step in which an'a'queous alcohol 'solution is used as described hereinafter. In the case of an expressed oil, the hydro oarbonsolventshuld be added tio form a miscella which may be refined as noted above or the alcohol may be added to the misoell'a Iprior to the rst refining step.

' Since a single phase dual solvent comprised of hydrocarbon and alcohol is recovered from the refined kmiscella. `according 'to the present invention, it is advantageous to recycle :this recovered solvent to a solvent extraction system 'for'extractng lthe oil from the seeds or beans lthus "eliminating'the need.for.separating the hydrocarbon from the alcohol-and producinga miscella which may be'used' directly in the present refining process.

Il'referablythe miscella to be treated Iis a four component-system comprising from about 10% to about 30% -glyceride oil and a solvent which may consist of from about 'to about.95% of a1hydrocarbonso1vent and fro'rn1about5% to about 20% of aqueous alcohol having an alcohol concentration of from about to vabout `Q89?) depending, in part, upon 'the nature of the alcohol. Miscellas falling broadly within the above ranges form aA-singlephase and can, in so far as the aqueous alcohol component is concerned, be considered to be in equilibrium since the oil-hydrocarbon solvent solution will not be y,Capable of dissolving any substantial additional quantity of aqueous .alcohol Vsolutions having concentrations as desjeribedabove. I .Y l 'Forfa'ny particular four component 'system such .as 1in` seed oil,`hexan`e,ethyl alcohol and water, the equilibrium percentages are interrelated and these mayeve'n'va'ry'wit'h variations in temperature. However, when exact quantities of, say, linseed oil and hexane are in solution and aqueous ethyl alcoholhaving a 90% concentration of alcohol is added thereto, the total quantity which can be dissolved in the oil-hexane solution is a definite amount which constitutes equilibrium. Variations in the relative proportions of any of the components will alter the equilibrium quantity of aqueous alcohol.

Equilibrium miscellas are desirable since they not only form a single phase but also will not take up any substantial quantity of alcohol or water from the alcoholic refining agent thus altering the relative proportions of the refining solution.

However a miscella which does not contain the equilibrium quantity of aqueous alcohol may be used in the present process since it will reach such equilibrium after being in contact with the alcoholic refining solution as described hereinafter. For this reason it is generally desirableto use an excess of the alcoholic refining agent so as to make available whatever quantities of alcohol '4 and water which might be required to establish equilibrium. When the miscella is in equilibrium, the refining agent may be easily separated from the miscella as, for example, by phase separation.

Although the process obtains peak eiiiciency when a specific combination of components are used in particular proportions, marked advantages nevertheless are obtained when the proportions fall within the above mentioned limits. For example, for certain vegetable oils a 30% miscella may produce the best results, while for other oils, a or 15% miscella may be the optimum. Likewise, for example, when hexane and ethyl alcohol form the solvent for linseed. oil, the proportion of each and the concentration of the aqueous alcohol solution for maximum efiiciency may be different than when a solvent composed of heptane and isopropyl alcohol is used with, for example, castor oil.

Be that as it may, specific examples of miscellas are described below as well as specific examples of the acid refining agents for treating such miscellas.

As specific miscellas which may be treated according to the present process there may be mentioned:

(l castor oil and 85% solvent, said solvent comprising 80% heptane and 20% of 88% isopropyl alcohol.

(2) 20% linseed oil and 80% solvent, said solvent cornprising 80% hexane and 20% of 90% ethyl alcohol.

(3) 20% soybean oil and 80% solvent, said solvent comprising 80% hexane and 20% of 88% isopropyl alcohol.

The miscella may be treated with either an acid relining agent or an alkaline refining agent or both of them in sequence. Although it is usually not customary to refine the oil first with the alkaline refining agent and then with the acid refining agent, this can nevertheless be done if desired. Where both refining agents are used the miscella is usually treated first with the acid refining agent for removing the foots and break and then with the alkaline refining agent.

The acid refining agent comprises a solution of alcohol in water in which is dissolved a small amount of an acidic material. The aqueous alcohol solution may have a concentration of from about 50 to 90% alcohol, preferably 70 to 85% alcohol, and the concentration of the acidic material in the alcohol solution may vary from about 0.01% by weight to about 5% but preferably from about 0.1% to 2.0%. The exact concentration of the acidic material will depend upon the nature of the acidic material, the nature of the oil being refined and the amount of impurities present therein as well as the oil concentration in the miscella. T he acidic material may be an inorganic acid, such as hydrochloric, sulfuric or phosphoric acid or acid salts thereof such as sodium bisulfate or may be an organic acid such as oxalic acid. Examples of specific acidic alcoholic solutions which may be used are:

(l) 7500 parts by weight of ethyl alcohol containing 5% by volume of methyl alcohol, 2500 parts of water, and 142 parts of hydrochloric acid solution containing 10% free HC1.

(2) 1500 parts by weight of ethyl alcohol containing 5% by volume of methyl alcohol, 500 parts of water, and 2 parts of oxalic acid.

(3) 7500 parts by weight of ethyl alcohol containing 5% by volume of methyl alcohol, 2500 parts of water and 5 parts of sodium bisulfate.

(4) 6000 parts by weight of ethyl alcohol containing 5% by volume of methyl alcohol, 200 parts of water and 2 parts of concentrated sulphuric acid.

(5) 2000 parts isopropyl alcohol, 1870 parts of water and 1 part of concentrated (37.5%) hydrochloric acid.

The total amount of the acidic refining agent used to refine the miscella may vary within fairly wide limits, as, for example, from about 1 part of the acidic solution to 10 parts of miscella to about 20 parts of solution to l0 parts of miscella although generally a ratio of 1:1 is satisfactory. Generally suliicient acidic refining agent of a particular concentration will be used so that .013% of 0.1% of the acidic material based on the quantity of oil to be refined will be present. It is preferable to use one of the higher acid concentrations Within the above ranges so as to permit direct recycling of the acid solution after treatment of the miscella and separation therefrom for as many times as the acid solution remains effective. Ultimately, the acidic solution loses its effectiveness due to accumulation of break and other impurities therein and must be purified. The purification of the alcohol solutions may be carried out by neutralizing with or without a subsequent filtering step to remove insoluble impurities and finally distilling the alcohol off, leaving behind those impurities which were soluble in the acidic alcohol solution. The distilled alcohol is condensed and may be returned to the acid refining stage with the addition of fresh acidic material. When the partially spent alcoholic acid solution is recycled directly to treat additional miscella, the acid value may be increased by the addition of an amount of acidic material to restore the desired free acid value.

The acid refined miscella, after separation from the acidic alcoholic solution, may be further refined with an alkaline reagent as described hereinafter or may be subjected to an alcohol washing operation with from about 10% to about 200% of a neutral or slightly alkaline aqueous alcohol solution. Following the washing step, the miscella is distilled so as to recover the single phase solvent mixture of hydrocarbon and alcohol, the residuum being a commercially acceptable break-free oil. The solvent mixture may be returned to a solvent extraction stage if such is used in combination with the refining process as mentioned above or it may be used to prepare a miscella or an oil for the refining process.

The acid refined oil obtained by the present method has been found to be better adapted to the further treatments that oils are subjected to, such as. heat bodying, bleaching or decolorizlng by clays or carbons, deodorizing and the like.

However, oil losses from a decolorizing operation may be reduced if the refined miscella is decolorized with clays or carbons before the oil solvent is removed since there will be less hold up of oil in the decolorizing material due to the lower viscosity and oil content of the miscella. Subsequent removal of the oil solvent produces a light colored oil directly.

As an example of the acid refining step, 50 parts of linseed oil miscella obtained by solvent extraction of ground, raw flaxseed with a mixed single phase hexane-ethanol solvent and containing 18 to 20% oil, is mixed with 50 parts of a 75% solution of ethyl alcohol containing hydrochloric acid in the proportion given in (l) above. The pH of the acidified alcohol solution was 2.9. After intimate contactwith the miscella and subsequentseparation in a separating column, the pH was 3.1 to` 3.2L fter passage through the separating column, the" recovered this` cella was clear and brilliant.

y,The recovered miscella was then `washed by mixing parts of miscella with 2 to l0 parts of substantially neu# tral aqueous alcohol having a strength of from about 50% to 90% in a mixing tank and then separating in a separating column. The wash alcohol may have a pH of from about 6 to about 7.5. An effective wash is ob-` tained when l parts of miscella is washed with 2.5 parts of 75% neutral aqueous alcohol. After separation, the oil was recovered from the miscella by distilling off the solvent. The oil product was clear and brilliant. It was found to be break free when tested according 'to the conditions of the Gardner heat break test. As recovered the oil had a color of 11, standard Gardner 1933, and heat bleached to a color of 7, an acid value of 1.2, and remained free of foots after several months storage. For comparisonoil that was recovered from the miscella that had notbeen subjected to the acid refining` treatment, had a color of 11, an acid value 2.3, and heat bleached to a color of 9, but was not break free when tested according to the Gardner heat break test and so-called foots were deposited from the oil during storage. A The alkaline refining step for removing foots and other impurities may be carried out with fresh miscella from the extraction system or may be carried out with the acid refined miscella as described above before carrying out the alcohol wash step. In this treatment the miscella to be refined is mixed intimately with an alcoholic solution containing a very small amount of an alkaline material. Thegalkaline material may be an organic amine or amide or an inorganic alkaline salt or hydroxide and may include such materials as triethanolamine, soda ash, sodiumhydr'oxide and the like. For example, the refining agent 'may comprise a 90% aqueous alcohol solution to which has' been added 0.1% soda ash. The amount of refining agent used may be varied within Wide limits although l0 parts of the agent to 100 parts of the miscella containing 20% oil has been found to effectively refine the oil by removing the foots. Soda ash will not generally remove free fatty acids which may be present in oil. Therefore, when such acids are present and when it is desired that they be removed, the alkaline material should be a soap forming alkali such as sodium hydroxide or the like which will convert the fatty acids to soaps which are then removed from the miscella. When an alkali hydroxide is used to remove both foots and fatty acids, the amount of alkali used should exceed by about 20% the amount of free fatty acids present'. A suitable alkaline refining agent may consist of alcohol having a concentration of from about 50% to about 90%, preferably from about 70% to 85%, to which is added from about 0.1% to about 2.0% of caustic soda or other alkaline material. Usually it is sufficient to treat a miscella with from 1 part to l0 parts of the alcoholic refining agent for each l0 parts of miscella, the amount depending upon the concentration and nature of the alkaline material and the extent of refining desired.

After thermiscella is thoroughly mixed with the alcoholic alkaline solution, the latter is separated from the miscella. This refined miscella may be washed with alcohol as `described above in connection with the acid refining step and then stripped to recover the mixed solvent for reuse. Or, if desired, the refined miscella inay be acid treated as described above before the washing step.

The above described acid and alkaline refining steps may be carried out at room temperatures or at higher temperatures depending on the boiling point of the particular hydrocarbon solvent being used. The recovery of the mixed solvent from the refined miscella is carried out at conventional distillation temperatures and the recovery of alcohol for' recycling to the retining and' washing steps may be' carried out at]tempera` tiires betweenA about l`7'5 F. and 212 F. depending on the alcohol used.

With reference' to the drawing, oil bearing seeds are passed through anv extraction system 11 whereby a miscella is obtainedv which may be an oil-hydrocarbon Vmiscella or, as noted hereinbefore,Y it preferably comprises the glyce'rde oil and hydrocarbon solvent as well as a portion of a lower aliphatic alcohol.

The miscella comprising thel glyceride oil, hydrocarbon solvent, lower aliphatic alcohol and water may be refined by acid treatment by passing the solution through lines,1`2 and 13 f o thel mixer 1:4 where it is intimately mixed with acidified alcohol as"` described hereinbefore.

This' mixture isVv then passed through line 1S to separating column 16 where a phaseV separation takes place between the' acid treated miscellaY and the acid treating agent. Instead of the separating column 16, any conventionalmea'ns or devices for separation of liquid phases such as a centrifuge, a solid-bowl centrifuge, or the like, may be used for this separation. The acid treated miscella is vi/ithdrawn` from column 1'6 through line 17 and, when an alkali treatment is desired, is passed through lines 18 and 19V to mixer 20 where the acid treated miscella is intimately mixed with alkaline alcohol as described hereinbefore. The mixture is passed through line 21 to a separating column 22 to permit phase separation between the alkali treated miscella and the alkaline-alcohol treating agent. As in the acid treating step", a centrifuge or the like, such as a solid-bowl centrifuge, may be used in place of the separating column 22 if desired.

When it isdesired to treat the miscella with an alkaline material before the acid treatment, the untreated miscella may be passed from line 12 directly' through line 19 to mixer 20 and the alkaline-treated miscella may be passed Vdirectly from separating column 22 to mixer 14 through lines 23 and 24.

It will also be understood that the lacid treatment or the alkaline treatment may be' eliminated. In the former case, the miscella is passed from line 12 through line 19 to mixer 20 and, after separation vin column 22, through lines 23 and 25 to mixer 26 foran alcohol wash treatment. In `the latter case, when the alkaline treatment is to be eliminated, Vthe acid treated miscella is passed from separating` column 16 through lines 17 and 25 directly to mixer 26. y

In the mixer' 26, the' treated miscella is mixed with neutral alcohol as described hereinbefore and is then passed through line 27 to separating column. 28 for phase separation of the washed treated miscella from the wash alcohol. As stated before, a centrifuge or the like may be used for this separation. The Washed and treated miscella iswithdravvn from column 28 through line 29 and is passed to a strippingfcolu'mn 30 where the oil solA vent and dissolved alcohol are'rer'noved from the refined glyceride oil which is withdrawn through line 31. The distillate from the stripper 30 comprises the oil solvent and alcohol and may be recycled directly to the extraction system 11. Of course, if a ypressing operation is used to recover the oil from the seeds, the oil solvent and alcohol may be added directly tothe expressed oil to form the oil-solvent-alcohol miscella, which f is passed through line 12.` Y l Returning new 'to the acid treating step, the treating agent is formed by mixing an acid, as -described hereinbefore, preferably an inorganic acid such as HCl, from tank 33 with aqueous 'alcohol solution in tank 3d. This treating agent is then passed through line 3S to mixer 1A*- lforrnixtirr'e"with themiscella. Each of `mixers id, 20 and 26 are equipped with mechanical agitators (not shown) or. other inean's to cause a thorough, intimate and uniform mixing of the vmiscella with the treating agent or wash alcohol.

The acid treating agent, after separation from the acidtreated miscella in column 16, is withdrawn therefrom through line 36 and may be recycled directly to storage tank 34 if the treating agent is not exhausted by accumulation of break and other impurities removed from the oil. The effectiveness of the recycled acid treating agent may be restored by addition of acid from tank 33 to provide the proper free acid value. Also any alcohol losses are made up by addition of alcohol to tank 34 as will be described hereinafter.

ln the alkaline treating step, a similar procedure may be followed, by mixing an aqueous solution of an alkaline material, as described hereinbefore, such as sodium carbonate or sodium hydroxide from tank 37 with aqueous alcohol solution in storage tank 38. This treating agent is then passed through line 39 to mixer 20 for mixture with the acid treated miscella or the untreated miscella.

The alkaline treating agent, after separation from the treated miscella in column 22, is Withdrawn through line 40 and may be recycled directly to storage tank 3S if the treating agent is not exhausted by accumulation of foots and other impurities removed from the oil. The effectiveness of the recycled alkaline treating agent may be restored by addition of alkaline material from tank 37 to provide the proper pH value. Alcohol losses may be made up by addition of alcohol to tank 38 as will be described hereinafter.

In the alcohol wash stage, alcohol from tank 41 is passed to mixer 26 for washing the treated miscella and, if desired, additional wash alcohol may be passed directly to a point near the top of the column 2S to effect further washing in the column itself. The wash alcohol, after separation from the miscella in column 28, is withdrawn through line 42 and may be recycled directly to tank 41 for reuse. lf the wash alcohol is slightly acidic due to the washing of an acid treated miscella directly after such treatment, as mentioned above, the acidic alcohol should be neutralized and this may be accomplished by the addition of a solution of an alkaline material such as sodium carbonate from tank 43 to tank 41.

lf desired, the wash alcohol in line 42 may be used to replenish possible alcohol losses in the acid treating stage and/or the alkaline treating stage. This may be accomplished by passing the separated wash alcohol from line 42 through lines 44 and 45 to line 40 and thence to tank 38 or when the wash alcohol is already acidic as mentioned above it may be passed through lines 44, 45 and 46 to line 36 and thence to acidified alcohol storage tank 34. If desired, the wash alcohol may he passed proportionately to both tanks 38 and 34.

After a period of operation, the acid and alkaline treating agents will contain so much break, foots and other impurities as to seriously impair the effectiveness of the treating agent which must then be purified.

In the case of the acid treating agent, a proportion of it may be withdrawn from line 36 through line 47 and passed to a neutralizer 48 Where an alkaline material is added to increase the pH value to 7 or more. The neutralized treating agent is then passed through lines 49 and 50 to a filter 51 for removal of foots and other insoluble impurities. The filtered treating agent still contains some dissolved impurities such as alcohol-soluble color materials, salts, and the like and it is therefore passed through lines 52 and 53 to alcohol recovery still 54. Here the alcohol is distilled off in a pure state and is passed through line 55 to condenser 56 and thence to storage tank 57. From tank 57 the alcohol is passed as needed through lines 58 and 59 to tank 41, or lines 58 and 60 to tank 3S, or through lines 58 and 6i to tank 34 for replenishing losses as mentioned hereinbefore.

The bottoms from still 54 are passed through line 62 to a separator 63 for separating black oil from the remaining materials including foots, Water, salts, and break which are withdrawn from the system via line 64. The black oil is removed through line 65.

In the case of the alkaline treating agent, a proportion of it may be withdrawn from line 40 through line 66 and passed to the neutralizer 48 where the pH thereof may be adjusted if necessary to a pH of 7 or above. The treating agent may be filtered in filter 51 and then passed directly to the still 54 through lines 52 and 53 or if the treating agent contains soaps, as would be the case if NaOH is used as the alkaline material, which would combine with the free fatty acids in the oil being treated, the neutralized treating agent may be passed directly through lines 49 and 67 to an acid hydrolysis step 68 for recovery of the fatty acids or the filtered treating agent from filter 5l may be passed from line 52 through line 69 to the step 68. After acid hydrolysis and separation of the fatty acids the alcohol component is withdrawn through line 70 and is passed through line 53 to still 54 for recovery of alcohol as described above.

Occasionally it may be desirable to purify the wash alcohol which has not been recycled to the acid treating or alkali treating stages. To accomplish this, the wash alcohol from column 2S may be passed from line 42 through line 71 to neutralizer 48 and thence through lter 51 and/or the acid hydrolysis step 68 and still 54 as referred to above.

lt will be seen that in operation some proportion of the alcohol may be continuously passing from the various separating columns 16, 22 and 28 directly back to the respective supply tanks 34, 38 and 4l and the remainder may be passed from each column continuously through lines 47, 66 and 71 to the purifying steps and the alcohol recovery still 54 for return to the tanks 34, 38 and/ or 41. Also a proportion of the wash alcohol from column 28 may be passed continuously to tank 34 and/or tank 38 as described above.

For simplicity, many conventional elements, such as valves, pumps, flow meters, cooling and heating coils, flow control devices and the like have been omitted from the drawing.

Although the present process has been described with reference to specific examples and to the attached drawing, it will be understood that various modifications and alterations may occur to those skilled in the art and that the description and liow sheet is therefore illustrative and is not intended as limiting the invention.

The scope of the present invention is defined by the appended claims.

What is claimed is:

l. A proces for refining miscellas containing from about 10% to about 30% of glyceride oils and from about 70% to about 90%l of a solvent therefor, said solvent containing from about to about 95% of a hydrocarbon solvent in which said glyceride oils are soluble and from about 5% to about 20% of an aqueous lower aliphatic alcohol having a concentration of from about to about 98%, said process comprising intimately contacting said miscella with an aciditied aqueous alcohol refining agent in which said alcohol is a lower aliphatic alcohol and has a concentration of from about 50% to about in water, the concentration of the acidic material in said acidied aqueous alcohol being not more than 5.0%, separating the treated miscella from the refining agent, washing the treated miscella with aqueous alcohol of 50 to 90% concentration, separating the wash alcohol from the miscella and separating the treated oil from the miscella.

2. A process as claimed in claim l wherein the aciditied aqueous alcohol contains acidic material selected from the group consisting of mineral acids, organic acids and inorganic acid salts.

3. A process as claimed in claim 2 wherein the acidic material is hydrochloric acid.

4. A process as claimed in claim l wherein the concentration of the acidic material n the acidied aqueous alcohol is from about 0.0l% to about 5.0%.

5. A process as claimed in claim 4 wherein about 10 parts of miscella are intimately contacted with from about 1 part to about 20 parts of the acidied aqueous alcohol.

6. A process as claimed in claim 5 wherein the miscella is intimately contacted with an amount of acidiied aqueous alcohol suicient to contain from about .013% to about 0.1% acidic material based on the amount of oil present in said miscella.

7. A process as claimed in claim 1 wherein about l0 parts of the treated miscella are washed with from about 2 parts to about 10 parts of aqueous alcohol.

8. A process as claimed in claim 1 wherein the hydrocarbon solvent comprises at least one hydrocarbon selected from the group consisting of aliphatic hydrocarbons having from 5 to 8 carbon atoms, aromatic hydrocarbons and chlorinated hydrocarbons. 1

9. A process as claimed in claim 1 and further comprising recycling a portion of the separated alcoholic re ining agent directly to the contacting step and removing impurities from the remaining portion of said refining agent and returning the purified refining agent to the contacting step.

10. A process as claimed in claim 1 and further comprising adding to a portion of the separated wash alcohol an acidic material and passing said portion to the contacting step.

References Cited inthe le of this patent 

1. A PROCESS FOR REFINING MISCELLAS CONTAINING FROM ABOUT 10% TO ABOUT 30% OF GLYCERID OILS AND FROM ABOUT 70% TO ABOUT 90% OF A SOLVENT THEREOF, SAID SOLVENT CONTAINING FROM ABOUT 80% TO ABOUT 95% OF A HYDROCARBON SOLVENT IN WHICH SAID GLYCERIDE OILS ARE SOLUBLE AND FROM ABOUT 5% TO ABOUT 20% OF AN AQUEOUS LOWER ALIPHATIC ALCOHOL HAVING A CONCENTRATION OF FROM ABOUT 85% TO ABOUT 98%, SAID PROCESS COMPRISING INTIMATELY CONTACTING SAID MISCELLA WITH AN ACIDIFIED AQUEOUS ALCOHOL REFINING AGENT IN WHICH SAID ALCOHOLS IS A LOWER ALIPHATIC ALCOHOL AND HAS A CONCENTRATION OF FROM ABOUT 50% TO ABOUT 90% IN WATER, THE CONCENTRATION OF THE ACIDIC MATERIAL IN SAID ACIDIFIED AQUEOUS ALCOHOL BEING NOR MORE THAN 5.0%, SEPARATING THE TREATED MISCELLA WITH AQUEOUS ALCOHOL AGENT, WASHING THE TREATED MISCELLA WITH AQUEOUS ALCOHOL OF 50 TO 9/% CONCENTRATION, SEPARATING THE WASH ALCOHOL FROM THE MISCELLA AND SEPARATING THE TREATED OIL FROM THE MISCELLA. 